Pierre prosper monnet



UNITED STATES PATENT OFFICE.

PIERRE PROSPER MONNET, QELYONS, FRANCE, ASSIGNOR TO LA SOCIETE CHIMIQUEDES USINES DU RHGNE ANCIENNEMENT GILLIARD, P. MONNET ET CARTIER, OF SAMEPLACE.

PROCESS OF MAKING AROMATIC ALDEHYD E PECIFICA'I-ION forming partofLetters Patent No. 613,460, dated November 1, 1898'. Application filedApril 29,1898. Seria1Nm67'9 1'78; m mmals.)

To all whom it may concern: have been obtained under the conditions andBe it known that I, PIERRE PROSPER MON- with the proportions stated; butthe condi= NET, of Lyons, France, have invented certain tions,especially the concentration of the acid new and useful Improvements inthe Producand the temperature, may be varied within 5 tion of AromaticAldehydes, of which the fol wide limits. lowing is a specification.Example 1: Benzaldehyde, three hundred Hitherto the conversion of methylderivakilograms of toluol, and seven hundred kilotives of the aromatichydrocarbons into arograms of sulfuric acid of sixty-five per cent.matic aldehydes has been ordinarily eflected are mixed together in anapparatus fitted with 10 in the following way, which may be described astirring device, and ninety kilograms of as an indirect method: The CHof the latmanganese binoxid are slowly added in the eral chain has beenconverted by the action form ofafine powder during vigorous stirring. ofchlorin into X--OH Ol or XOHOl and The temperature is maintained atabout 40 the aldehydes have been produced from those centigrade. Afterall the binoxid of manga- 15 chlorination products by subsequentoxidanese has been added the stirring device is tion. Apart from thecost of chlorination kept in operation for some time in order to thisprocess has the drawback that a certain complete the reaction. Themixture of ben amount of chlorin or chlorinated products enzaldehyde andtoluol is then distilled with ters into the aromatic nucleus, and theresteam, and the separation is effected in the 20 moval of theseproducts generally presents well-known manner. difficulties. In somecases-e.g.,in the manu- Example 2: Toluyaldehyde, (O.M.P.) The factureof benzaldehyde-this drawback is xylenes are treated as stated inExample 1 at not of much consequence, but in others-e. g., a temperatureof about 25. The oxidation in the manufacture of toluylic aldehydesittakes place more readily than in the case of 25 is very appreciable.toluol.

I have discovered that aldehydes can be The process of manufacturediscovered by produced by direct oxidation if care is taken me can alsobe applied to produce substituted that the oxidizing agent is always inthe presaldehydes. For example, orthochlorbenzah ence of a large excessof the CH compound, dehyde can be easily produced by treating or 30 andthis constitutes the characteristic feature thochlortoluene according tothe method deof the present invention. Hitherto the direct scribed inExample 1. oxidation of the CI-I of aromatic compounds Nitro derivativesof the hydrocarbons, such has practically always yielded carboxylic asnitrotoluene and nitroxylene,also yield the acids. By this simpleexpedient discovered corresponding aldehydes. The behavior of 35 by methe further progress of the oxidation the hydroxyl derivatives towardoxidizing i. e., the formation of carboxylic acidcan be agents under theabove conditions varies.

almost completely prevented. Thus the methyl ether of paracresol givesan The reaction which I have discovered is caaldehyde withoutdifficulty, while the orthopable of general application. cresolcompounds give no aldehyde under the 0 Up to the present I have obtainedthe best same conditions. results by the use of freshly-precipitatedman- The sulfonic derivatives of aromatic hydroganese binoxid or Weldonmud and sulfuric carbons, their chlorids, amids, and esters, as

acid as the oxidizing agent; but according to well as the acetylated andmethylated amido my experience other suitable oxidizing agentsderivatives, give no aldehydes under the same 5 mayalso be employed,carebeing always taken conditions.

to have a large excess of the product to be oxi- What I claim, anddesire to secure by Letdized at the close of the reaction. ters Patent,is-- The following examples may serve to illus- 1. The process ofmanufacturing aromatic trate the method of application of this newaldehydes by the direct oxidation of the 50 process of manufacture. Thebest yields methyl group in compounds of the aromatic roe hydrocarbonseries, which process consists in treating the said compound with anoxidizing agent in the presence 6f a large excess of the said compoundand separating from the unaltered material the aldehyde produced,substantially as described.

2. The process of aldehydation of the methyl group in compounds of thearomatic hydrocarbon series, which process consists in the treatment ofthe said compound with an oxidizing agent in such a proportion that theoxidizing agent is insufficient for the oxidation of the total methyl toaldehyde and subsequently in separating from the unaltered material thealdehyde produced.

PIERRE PROSPER MONNET.

Witnesses:

RODOLPHE PFISTER, Mimics TACI-ION.

